The projectiles disclosed in the afore-mentioned applications generally include a plurality of pre-penetrator elements mounted in a casing one behind the other. The pre-penetrator elements of this projectile consist of hard metal or metal of high density and the projectile also includes a main penetrator body which is axially disposed behind the penetrator elements and contiguous thereto. This main penetrator body also is generally made of a metal of high density. By providing a plurality of pre-penetrator elements of different sizes or materials, a desired decrease in mass of the projectile arrangement is thereby realized so that, after penetration of an exterior armor, there remains sufficient projectile mass in the form of the main penetrator body for the penetration (i.e. destruction) of the main armor plating disposed behind the exterior armor.
Projectiles of the afore-described type are, at penetration of a plurality of target plates in a direction transversely to the longitudinal axis of the projectile, exposed to certain effective loads, which may lead to a premature bending failure (breaking) of the projectile. If the penetration channel is inclined with respect to the direct linear extension of the projectile flight path, the main penetrator body can, after impacting on the main armor, negatively affect the latter and thereby the effectiveness of the projectile in a very sensitive manner.
In accordance with the allowed and co-assigned U.S. application Ser. No. 412,794, the desired successive reduction of the pre-penetrator cores at penetration of the target is achieved in that the configuration of the abutting pre-penetrator elements and the mating surrounding casing are designed in such a way that at the inclined impact of the projectile on the target certain transverse forces act on the pre-penetrator elements with adaptation for different targets so as to lead to a controlled pre-penetrator reduction. Such a tolerating of the dimensioning has proven to be quite cumbersome. In view of the fact that the casing surrounding the pre-penetrator elements must in the known arrangements have the same wall thickness from front to back, the danger exists that it, as a result of the laterally acting forces, breaks prematurely at rearwardly located loci and thereby the desired effect of the successive breaking of the individual pre-penetrator elements is not achieved.
According to application Ser. No. 476,408 the successive braking of the pre-penetrator cores is achieved by shaping the individual cores in such a way that in the abutting surface region they connect as pivotal joints and that fracture zones in the outer casing are present adjacent to these pivotal joints. Such a construction of a projectile is quite complex, since the front and rear surfaces of the cores must have from front to back increasing inclinations with respect to the longitudinal axis of the projectile for the purpose of achieving the desired breaking up. This makes an exchange of the cores between each other for adaptation to different target characteristics of the target plates impossible.
A standard armor-piercing penetrator shell, as described in U.S. Pat. No. 4,108,072 of Trinks has a front end constituted by a stack of high-density core elements held in a containment sleeve. This stack is secured to the front end of high-density main penetrator body. Shock-absorbing layers of resin-bound hollow microspheres are provided between the core elements. The front end of the core-element stack is provided with a normally hollow tip mainlY serving aerodynamic purposes.
When such a projectile strikes a target, for instance of laminated or cellular armor, the core elements operate the original hole. The shock-absorbing layers between the elements prevents the impact shock from being transmitted back to the main penetrator body, so the same remains intact and can transfer its mass and energy to the underlying armor layer.
Thus, this patent discloses a penetrator projectile in which the individual cores are not in abutting direct contact with each other, but are separated from each other by means of dampening elements. Therefore, the Trinks projectile loses at impact on the target the optimum guidance and centering between the individual cores as a result of the "spreading out" of the casing so that a controllable decomposition of the projectile body is not possible in the Trinks projectile, because such body is already decomposed at impact on the first (outer) target plate. In contradistinction thereto, in the projectile of the invention as defined in the claims, at penetration of the first target plate, the first pre-penetrator core decomposes up to the pre-selected fracture or separation region and is separated from the remaining projectile bodies so that for the next second target plate the next following second pre-penetrator core with its cutting edge is available. Thus, each one of the target plates consumes only the corresponding frontally disposed pre-penetrator cores, which means that the result of the material properties of the material making up the pre-penetrator core it disintegrates due to its fragility into sufficient small pieces so that it does not represent an obstacle for the next following main penetrator.
With all of the afore-described embodiments the casing has the same closed section in the region of each fracture zone of the projectile. This brings about the danger, that the projectile breaks up prematurely in a more rearwardly disposed region and thereby makes impossible the desired successive breaking up from front to back. Moreover, the known "stacked projectiles" have three or more pre-penetrators; they are therefore not adaptable for acting against a modern armor which generally has three armored plates disposed one behind the other at predetermined distance from each other and which target plates have generally different thicknesses.